/**
 * 
 */
package runoob;

import java.util.*;



/**
 * @author blank
 *
 */
public class mapDemo {
	public static void main(String[] args) {
		Map<String, String> map = new HashMap<String,String>();
		map.put("1", "value1");
		map.put("2", "value2");
		map.put("3", "value3");
		
		
		//第一种，普遍使用，二次取值
		System.out.println("通过Map.keySet遍历key和value");
		for (String key:map.keySet()) {
			System.out.println("key="+ key+"and value"+map.get(key));
		}
		
		//第二种
		System.out.println("通过Map.entrySet使用iterator遍历key和value");
		Iterator<Map.Entry<String, String>> it =map.entrySet().iterator();
		while(it.hasNext()) {
			Map.Entry<String, String> entry =it.next();
			System.out.println("key= "+entry.getKey()+"and value= "+entry.getValue());
		}
		
		//第三种，容量大时
		System.out.println("通过Map。entrySet遍历key和value");
		for(Map.Entry<String, String> entry:map.entrySet()) {
			
		System.out.println("key= "+entry.getKey()+"and value="+entry.getValue());
		}
		
		//第四种
		System.out.println("通过Map.values()遍历所有的value,但不能遍历key");
		for(String v:map.values()) {
			System.out.println("value="+v);
		}
		}
		
	
}
